About the Authors xi
Foreword xiii
Preface xv
Acknowledgment to the Second Edition xvii
Acknowledgment to the First Edition xviii
About the Companion Website xix
1 Introduction 1
1.1 Wind energy and Planet Earth 1
1.2 Winds of the world 3
1.3 From windmills to wind turbines 7
1.4 Power, energy, and performance 15
1.5 Coming up-to-date 21
Appendix 1.A: Energy units and conversions 25
Co2 emissions per fuel type 25
Co2 emissions in transportation 26
Self-assessment questions 26
Problems 27
Answers to questions 27
References 28
2 Capturing the wind 29
2.1 Wind speed and power 29
2.2 Wild wind 34
2.2.1 Introduction 34
2.2.2 Wind statistics 36
2.2.3 Mapping and forecasting 45
2.3 Predicting turbine output 51
Self-assessment questions 55
Problems 56
Answers to questions 57
References 58
3 Wind turbines 59
3.1 Turbine types and sizes 59
3.2 Aerodynamics 64
3.2.1 Rotor efficiency and the Betz limit 64
3.2.2 Lift and drag 67
3.2.3 Rotor speed 74
3.2.4 Rotor blades 80
3.2.4.1 Choosing airfoils 80
3.2.4.2 Stall and pitch control 83
3.3 Mechanics 86
3.3.1 Gearboxes 86
3.3.2 Towers 89
3.3.3 Vibration and fatigue 90
3.4 Electrics 98
3.4.1 Alternating current (AC) electricity 98
3.4.2 Generators 106
3.4.2.1 Introductory 106
3.4.2.2 Synchronous generators and gearless wind turbines 111
3.4.2.3 Asynchronous generators 116
3.5 Turbine control 125
3.6 Onshore wind farms 130
3.6.1 Introductory 130
3.6.2 Siting and spacing 132
3.6.3 Monitoring and control 136
Self-assessment questions 138
Problems 138
Answers to questions 141
References 142
4 Fundamentals of offshore system 143
4.1 Introduction 143
4.2 Offshore wind power fundamentals 146
4.3 Tackling intermittency of wind power 149
4.3.1 The sun, wind, and wind-resource map 149
4.3.2 Wind and waves 152
4.3.3 Wind-resource maps 156
4.3.4 Minimum wind speed to produce power and power curve of a turbine 156
4.3.5 Storage of energy from offshore wind 156
4.3.5.1 Hydrogen production using offshore wind—the Japanese “Jidai” concept 159
4.3.5.2 ASIDE: potential of green hydrogen 159
4.3.5.3 BATWIND project 160
4.4 Offshore systems and choice of foundations 160
4.4.1 Turbines and foundations 160
4.5 Offshore wind farm case studies 167
4.5.1 Case study: Horns Rev 2 167
4.5.2 Case study: London Array 170
4.5.3 Case study: World’s first floating wind farm 173
4.6 Bringing the power ashore 175
Appendix 4.A: Specifications of turbines 177
Appendix 4.B: Details of offshore wind farms on different types of foundations 178
Self-assessment questions 181
Problems 181
Answers to questions 182
References 183
5 Offshore wind farm engineering 185
5.1 Conceptual design of wind arms 186
5.1.1 ASIDE 1: spacing of turbines and changes in geology and water depth 186
5.2 Cases studies 188
5.2.1 Dogger bank offshore wind farm 188
5.2.2 Westermost rough wind farm 189
5.2.3 Karehamn offshore wind farm 189
5.2.4 West of Duddon sands 191
5.2.5 Development of offshore wind in the USA 191
5.2.6 Wind farm development in China 192
5.3 Detailed site investigation 196
5.3.1 ASIDE 2: observed scour in Robin Rigg Wind Farm which had to be decommissioned mid-way in the lifecycle 198
5.3.2 Variability in ground profiles 198
5.3.3 Stages of investigation for ground model 201
5.3.3.1 Geological study 201
5.3.3.2 Geophysical survey 202
5.3.3.3 Geotechnical investigation 203
5.4 Offshore construction 203
5.4.1 Introduction 203
5.4.2 Choosing foundation systems 204
5.5 Engineering models of wind turbine systems 207
5.5.1 Load transfer mechanism from the structure to the ground 207
5.5.2 Modes of vibration 208
5.5.3 Mechanical model of the whole system 210
5.5.3.1 Why are foundations important? 213
5.6 Loads on a wind turbine structure 213
5.6.1 Load cases for foundation design 215
5.7 Frequencies of loads acting on wind turbine structure 220
5.8 Design requirements 222
5.9 Summary of offshore wind turbine engineering 224
Appendix 5.A: Modes of vibrations 224
5.A.1 Wind turbine systems on deep foundation 224
5.A.1.1 Modes of vibration of GBS structure 225
Appendix 5.B: Foundation stiffness 225
5.B.1 Definition of terms (KL, K R, and KLR) through the example of a cantilever beam 226
Appendix 5.C: Construction of wind and wave spectrum 228
5.C.1 Construction of wind spectrum 228
5.10 Kaimal spectrum 229
5.11 Construction of wave spectrum 230
Self-assessment questions 231
Problems 232
Answers to questions 235
References 236
6 Operations and maintenance (O&M) 237
6.1 Introduction 237
6.2 Maintenance practices and tools 238
6.3 Wind turbine O&M data 238
6.3.1 Onshore WT O&M data 239
6.3.2 Offshore WT O&M data 243
6.3.3 Onshore and offshore O&M data analysis 243
6.3.4 The impact of O&M on the LCOE 247
6.3.4.1 Land-based WT 247
6.3.4.2 Offshore wind turbines 249
6.4 Statistical tools of reliability analysis 250
6.4.1 Failure modes, effect, and criticality analysis (FMECA) 251
6.4.1.1 Failure modes 251
6.4.1.2 Failure causes 251
6.4.1.3 Failure effects 252
6.4.1.4 Criticality of failure modes 253
6.4.2 Logistic regression (LR) 254
6.4.3 Artificial neural networks (ANNs) 254
6.5 Workforce education and training 255
6.5.1 Safety training 255
6.6 Summary 256
Self-assessment questions 256
Problems 257
Answers to questions 266
Appendix 6.A: Hurricanes, typhoons, and cyclones 266
Appendix 6.B: Price of OWF: Normalized cost: LCOE breakdown for European wind farms 267
References 268
7 Grid integration 269
7.1 Setting the scene—national grids 269
7.2 Electricity markets and types of power generators 273
7.2.1 Peaker plants 275
7.2.2 Baseload plants 277
7.3 Connecting to the grid 277
7.3.1 Grid strength and fault levels 277
7.4 Electrical quality 281
7.5 Large-scale wind power 284
7.6 Intermittency and variability 285
7.7 Grid-friendly wind power plants 288
7.8 Capacity credit and backup generation 289
7.9 The variability challenge and solutions 290
7.9.1 Geographical diversity/transmission interconnections 291
7.9.2 Long-distance transmission lines 291
7.9.3 Grid flexibility 292
7.10 Are 100% renewable energy grids feasible? 293
7.11 Grid reliability 294
7.12 The grid of the future 296
Self-assessment questions 296
Problems 297
Answers to questions 299
References 300
8 Wind energy growth and sustainability (cost, resources, environment) 301
8.1 Affordability 302
8.1.1 Upfront capital and installation costs 302
8.1.1.1 Onshore wind turbines 303
8.1.1.2 Offshore wind turbines 304
8.1.2 Operation, maintenance, and cash flow 307
8.1.2.1 Levelized cost of electricity (LCOE) 309
8.2 Resource availability 311
8.2.1 Raw material primary resources 312
8.2.1.1 Blades 313
8.2.1.2 Rare earth elements (REE) 313
8.2.2 Wind turbine decommissioning 314
8.2.3 Wind turbine recycling 314
8.2.3.1 Blades 314
8.2.3.2 Rare earth elements (REE) 316
8.3 Environmental and social aspects 317
8.4 Land use 320
8.5 Water use 322
8.6 Life-cycle analysis 322
8.7 Landscape and amenity 325
8.8 Birds and bats 329
8.9 Farming 332
8.10 Seabirds, fish, and marine conservation 333
Self-assessment questions 335
Problems 336
Answers to questions 337
References 337
Index 339
